Arsenal's Samir Nasri has attracted the attention of Chelsea who are considering an approach for the midfielder. Photograph: Akira Suemori/AP

Chelsea are monitoring Samir Nasri's situation at Arsenal and could challenge Manchester United for the France international's signature should their pursuit of alternative targets, principally Tottenham Hotspur's Luka Modric, be frustrated.

Arsenal have, as yet, failed to convince Nasri to extend his stay at the Emirates Stadium, where the midfielder, a £15.8m signing from Marseille in 2008, has entered the final 12 months of his contract. United are expected to make a formal offer for the 24-year-old, with Arsenal wary of allowing the player to wind down his contract and leave for nothing next summer, but Chelsea are also actively considering stepping up their own interest given the Frenchman's anticipated availability.

Nasri is not yet considered a front–line target by Chelsea's new manager, André Villas-Boas – who intends to scrutinise his squad when the players return to pre-season training next week – with the club having targeted Modric as their preferred creative midfield recruit. An opening bid of about £22m has been rejected by Spurs, and the Tottenham chairman, Daniel Levy, who will meet Modric's representatives next week, has made clear his objections to the prospect of losing the Croatia international. Should that pursuit continue to be blocked, Chelsea will switch their attentions more concertedly towards Nasri.

The Frenchman is apparently undecided as to where his future lies, but is well aware that personal terms will be more lucrative at United and Chelsea. There is an acceptance, too, at Arsenal, who had hoped to tie the player down to a new five-year contract worth £90,000 a week, that they cannot compete financially with the midfielder's other suitors. Arsenal's position is further complicated by the possibility that Manchester City may enter the fray later in the summer, particularly if they fail to secure Udinese's highly-rated Chilean winger Alexis Sánchez.

City anticipate securing the £7m signing of Arsenal's France full-back Gaël Clichy – another player who has entered the final year of his deal at the Emirates Stadium – next week, with the Londoners themselves close to getting Gervinho from Lille for about £10m. The Ivory Coast forward scored 15 goals en route to winning the French title last season but told France Football that he had "no hesitation" in agreeing the move to Arsenal.

Adel Taarabt, the Queens Park Rangers midfielder who said last month that Chelsea and Arsenal were interested in him, has been targeted by Paris St-Germain following the club's takeover by Qatari Sports Investments. Reports in France suggest a bid of around £13.5m has been tabled by the French club for the 22-year-old, though QPR, who have yet to add to their ranks since their promotion to the Premier League, are expected to drive that price higher given that Spurs had a sell-on clause, believed to be 40% of the profit, inserted into the £600,000 deal that took Taarabt to Loftus Road last summer.

Chelsea have allowed the Dutch international defender Jeffrey Bruma to join the German club Hamburg on an initial season-long loan, with the option of a further 12 months. Frank Arnesen is the sporting director at Hamburg and has moved for the 19-year-old just weeks after leaving a similar post at Stamford Bridge.

The midfielder Jack Cork could also be on his way out of Chelsea as the Championship club Southampton are close to agreeing a transfer for the 22-year-old, who spent last season on loan at Burnley.